Many different kinds of wiping cloths are commercially available. Common types are made of paper or nonwoven fabrics, and are often used as damp wiping cloths or are supposed to absorb fluid. Such wiping cloths are used as wet wipes or as fluid-absorbent cloths, for example, in baby care, in the cosmetics sector, for example, for the treatment of acne, for removing dirt in the household, in the bathroom, or for cleaning buildings, for applying or removing or removing care substances or cosmetic substances to the skin, for applying or removing medical substances, or for personal hygiene. These are structures that usually are supposed to possess a high water absorption or fluid absorption capacity, for this purpose of use. In addition to water, these structures frequently contain many different kinds of lotions based on oils or oil/water mixtures, and/or chemical substances that support the cleaning effect, together with the fiber surface. Since the products are often used with the hands, the products are offered either in voluminous, bulky form, or are folded or bunched together during use, so that they can be handled more easily and comfortably during use.
Three-dimensional structures for use as a wiping cloth are described in International Published Patent Application Nos. WO 00/18998 and WO 99/07273. Composites of at least one or two nonwoven fabrics and extruded, biaxially stretched nets, for example, made of polypropylene, are conventional. After lamination, for example, by partial bonding caused by pressure and temperature, they develop raised areas in the third dimension due to shrinkage, and thereby become more voluminous. These raised areas are relatively irregular because of the shrinkage in both directions, i.e., in the lengthwise and crosswise orientation of the monofilaments, and they are not particularly appealing optically. Bonding of the two nonwoven fabrics occurred through the net, as the result of hot bonding in a calender under pressure and temperature, at certain points or in a pattern.
A nonwoven fabric that is made up of at least one unidirectionally stretched spunbond and a staple fiber nonwoven fabric bonded to it is described in European Published Patent Application No. 0 814 189. The laminate is characterized by a high volume and a good textile feel.
Three-dimensionally structured fiber fabrics are conventional. German Published Patent Application No. 199 00 424 describes three-dimensionally structured combinations of endless fiber layers and staple fiber layers that are thermally bonded together in the form of a regular pattern. The development of the three-dimensional structure occurs by using fiber layers with a different shrinkage capacity. By triggering the shrinkage, the staple fiber layer is given a three-dimensional structure. In this connection, however, it has been shown that the resulting three-dimensional structure is irregular, since the sequence of elevations and depressions occurs according to a random pattern.
Examples of such laminates are fiber fabrics of at least one or two nonwoven fabrics and extruded, biaxially stretched nets, for example made of polypropylene (referred to as “PP” hereinafter). These develop raised areas in the third dimension after lamination, due to shrinkage. These raised areas are relatively irregular, because of the shrinkage in both directions, i.e., the lengthwise and crosswise orientation of the monofilaments of the stretched PP net, among other things, and they are not particularly appealing optically. Bonding of the two nonwoven fabrics usually occurs through the net, as the result of hotmelting in a calender under pressure and temperature, at certain points or in a pattern.
It is an object of the present invention to provide three-dimensionally structured fiber structures that demonstrate a clearly increased fluid absorption capacity and, at the same time, are characterized by a regular three-dimensional pattern. In other words, fiber structures with a high fluid absorption capacity with a regular structure and a large volume, i.e., bulkiness, are supposed to be produced by the present invention, i.e., by taking specific measures according to the present invention, it is supposed to be possible to predetermine a high level of water absorption and, at the same time, the structure of the three-dimensional elevations and depressions is supposed to be predetermined, and the randomness and the irregularities in structure connected with it are supposed to be prevented.